16. Genetic recombination in several groups through the use of pili (minute tubes that allow the passage of the bacterial chromosome from the donor cell to the recipient cell
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21. Nitrogen wastes are excreted & cycled by bacteria Nitrogen in Plant & animal protein Ammonia nitrogen Is excreted in urine Bacteria convert Ammonia to usable Nitrate fertilizer
25. B . Class Cyanobacteriae—The Blue-Green Bacteria 1. Introduction a. Pigments 1) Chlorophyll a 2) Phycocyanin 3) Phycoerythrin b. Can both fix nitrogen and produce oxygen 2. Distribution a. Widely distributed in fresh and marine waters b. Some precipitate carbonate deposits (travertine)
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27. 3 . Form, metabolism, and reproduction a. Form 1) Cells often occur in chains or hair-like filaments 2) Some species occur as colonies 3) Color varies depending on pigments present, although half are blue-green b. Metabolism • store carbohydrates, lipids, and the nitrogenous cyanophycin c. Reproduction 1) New cells formed by fission 2) New colonies may be formed by fragmentation at: a) Heterocysts (nitrogen-fixing cells) b) Akinetes 3) Genetic recombination
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29. 4. Blue-green bacteria, chloroplasts, and oxygen a. Symbiotic origin of chloroplasts from blue-green bacteria • blue-green bacteria occur symbiotically and function essentially as chloroplasts in host organism b. Speculation that chloroplasts originated as prochlorobacteria 5. Human relevance of the blue-green bacteria a. Occur at bottom of food chains b. Production of blooms c. Poisons d. Spirulina used as food e. Undesirable effects in human water supplies f. Nitrogen fixation
47. The lambda phage which infects E. coli demonstrates the cycles of a temperate phage.
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66. D . Viral Reproduction 1. Viruses replicate only at the expense of their host cells 2. Viruses must become attached to a susceptible cell 3. Once inside the host cell, their DNA or RNA directs the synthesis of new viral particles 4. Some viruses mutate rapidly 5. Viruses may affect the metabolism of their host cells 6. Infected cells can produce interferon which protects uninfected cells
83. Viruses are host specific – a protein on the surface of the virus has a shape that matches a molecule in the plasma membrane of its host, allowing the virus to lock onto the host cell.
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